Prodrug compositions, prodrug nanoparticles, and methods of use thereof

ABSTRACT

The present invention encompasses prodrug compositions, nanoparticles comprising one or more prodrugs, and methods of use thereof.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.13/641,252, filed Jan. 29, 2013, which is a is a US National of PCTApplication PCT/US2011/032744, which claims the priority of U.S.provisional Application No. 61/324,464, filed Apr. 15, 2010, each ofwhich is hereby incorporated by reference in its entirety.

GOVERNMENTAL RIGHTS

This invention was made with government support under R01 AR056468, R01HL094470, and U54 CA119342 awarded by the National Institutes of Health.The government has certain rights in the invention.

FIELD OF THE INVENTION

The present invention encompasses prodrug compositions, nanoparticlescomprising one or more prodrugs, and methods of use thereof.

REFERENCE TO SEQUENCE LISTING

A paper copy of the sequence listing and a computer readable form of thesame sequence listing are appended below and herein incorporated byreference. The information recorded in computer readable form isidentical to the written sequence listing, according to 37 C.F.R.1.821(f).

BACKGROUND OF THE INVENTION

Known active compounds with in vitro activity may not be accessible forin vivo therapy because of difficulties in delivery of these compounds.For instance, the compound may have a short in vivo half-life, renderingthe compound practically useless in vivo. Similarly, a compound may beunstable in vivo, converting to an inactive compound under physiologicalconditions. Or alternatively, a compound may be associated withsignificant toxicity, rendering its in vivo use difficult. There is aneed, therefore, for a method of delivering these active compounds thatboth maintains the activity of the compound in vivo, and directsdelivery to a desired target cell, avoiding potential toxicity.

SUMMARY OF THE INVENTION

One aspect of the present invention encompasses a composition for invivo delivery of a compound to a target cell. The composition comprisesa non-liposomal particle and at least one prodrug. The outer surface ofthe particle is a membrane comprised of the at least one prodrug, and isfurther comprised of about 100% to about 60% phospholipid, wherein theouter surface of the particle is capable of fusing to the outer leafletof the target cell membrane in vivo, such fusion resulting in transferof the prodrug from the particle to the outer leaflet of the targetcell. The prodrug comprises a compound of less than about 3000 da linkedto an acyl moiety of a phosphoglyceride, wherein the compound may bereleased from the phosphoglyceride backbone via enzyme cleavage. Theprodrug substantially remains in the outer surface membrane of theparticle until transfer of the prodrug to the outer leaflet of thetarget cell, and the prodrug is further transferred from the outerleaflet to the inner leaflet of the target cell membrane, resulting inrelease of the compound intracellularly via cleavage of the enzymecleavable linkage.

Another aspect of the invention encompasses a method for in vivodelivery of a compound to a target cell. The method comprisesadministering a composition to a subject, the composition comprising anon-liposomal particle and at least one prodrug in a pharmaceuticallyacceptable carrier. The outer surface of the particle is a membranecomprised of the at least one prodrug, and is further comprised of about100% to about 60% phospholipid, wherein the outer surface of theparticle is capable of fusing to the outer leaflet of the target cellmembrane in vivo, such fusion resulting in transfer of the prodrug fromthe particle to the outer leaflet of the target cell. The prodrugcomprises a compound of less than about 3000 da linked to an acyl moietyof a phosphoglyceride, wherein the compound may be released from thephosphoglyceride backbone via enzyme cleavage. The prodrug substantiallyremains in the outer surface membrane of the particle until transfer ofthe prodrug to the outer leaflet of the target cell, and the prodrug isfurther transferred from the outer leaflet to the inner leaflet of thetarget cell membrane, resulting in release of the compoundintracellularly via cleavage of the enzyme cleavable linkage.

Other aspects and iterations of the invention are discussed in moredetail below.

BRIEF DESCRIPTION OF THE FIGURES

The application file contains at least one photograph executed in color.Copies of this patent application publication with color photographswill be provided by the Office upon request and payment of the necessaryfee.

FIG. 1A-B depicts light microscopy images of cells. The cells aretreated with (A) doxorubicin delivered by prodrugs and (B) freedoxorubicin drug.

FIG. 2 is a graph depicting the effect of free doxorubicin drug andprodrug doxorubicin on cell proliferation compared to no treatmentcontrol.

FIG. 3 is a graph depicting the angiogenic response to doxorubicin andpaclitaxel prodrugs incorporated into integrin-targeted PFCnanoparticles in the rat matrigel plug model (n=2/group).

FIG. 4A-B depicts two micrographs. The micrographs illustrate (A)non-significant change in angiogenesis contrast enhancement at 1.5T withnon-prodrug paclitaxel, and (B) the angiogenic response to paclitaxelprodrugs incorporated into integrin targeted PFC nanoparticles in thevx2 tumor model (n=2/group) in rabbit.

FIG. 5 depicts doxorubicin and available sites for functionalmodification.

FIG. 6 depicts the synthesis scheme of PC-doxorubicin conjugate 1.

FIG. 7 depicts the PC-doxorubicin (PC-DXR) candidate-1 prodrug, and the1H NMR (400 MHZ) spectroscopy of that prodrug.

FIG. 8 depicts the synthesis scheme of taxol prodrugs.

FIG. 9 is a graph depicting the antiproliferative effect ofPC-paclitaxel (PC-PXTL) prodrug on 2F2B endothelial cells.

FIG. 10 depicts the synthesis scheme of cis-platin prodrugs-1.

FIG. 11 depicts the synthesis scheme of cis-platin prodrugs-2.

FIG. 12 depicts the synthesis scheme of methotrexate prodrugs.

FIG. 13 depicts the synthesis scheme of brotezomib prodrugs.

FIG. 14A-B depicts two synthesis schemes, specifically, the synthesisscheme of a myc-inhibitor prodrug[[s]] (A) and an alternative variant(B).

FIG. 15 depicts the synthesis scheme of lenalidomide prodrugs.

FIG. 16 depicts the synthesis scheme of fumagillin prodrugs 1 (top) andfumagillin prodrugs 2 (bottom).

FIG. 17 depicts the synthesis scheme of photodynamic therapy (PDT)prodrugs.

FIG. 18A-B depicts two synthesis schemes, specifically, the synthesisscheme for a docetaxel prodrug (A) and an alternative variant (B).

FIG. 19A-B depicts two graphs illustrating that fumagillin dissolved ina lipid membrane is stable in vitro but rapidly lost in vivo. (A) Invitro release of fumagillin is sustained over 4 days. (B) In vivorelease of fumagillin occurs in a matter of minutes.

FIG. 20 depicts a graph showing that administration of a fumagillinprodrug targeted with αvβ3 reduces implant volume enhancement.

FIG. 21A-B depicts two graphs illustrating that an αvβ3 targetedfumagillin prodrug reduces cellular proliferation. In (A) cellularproliferation is measured by a CyQuant Assay, and in (B) cellularmetabolic activity is measured by an Alamar blue assay in HUVEC cells.

FIG. 22 depicts a graph illustrating the results of an alamar blue assaywith a docetaxel prodrug. Seven thousand 2F2B cells/well were exposed toan αvβ3 targeted particle comprising either no drug (control),docetaxel, or docetaxel prodrug.

FIG. 23A-C depicts micrographs and a graph demonstrating the effect of adocetaxel prodrug on tumor growth. (A) The four panels illustratemicrographs of tissue at baseline and at 3 hr postinjection exposed toeither an αvβ3 targeted particle comprising a docetaxel prodrug or anαvβ3 targeted particle without docetaxel. (B) Tumor volume is decreasedwith the administration of a docetaxel prodrug. (C) Illustration oftumor volume with an αvβ3 targeted particle comprising a docetaxelprodrug (left panel) or an αvβ3 targeted particle without docetaxel(right panel).

FIG. 24A-B depicts the effect of a docetaxel prodrug on theproliferation index. (A) Particles targeted with αvβ3 and comprising adocetaxel prodrug reduce the proliferation index of tumor cells. (B)Micrographs demonstrate the reduced proliferation after exposure to anαvβ3 targeted particle comprising docetaxel. Proliferation index equalsthe PCNA positive area divided by the methyl green nuclear positive onlyarea.

FIG. 25A-B depicts the effect of a docetaxel prodrug on the apoptoticindex. (A) Particles targeted with αvβ3 and comprising a docetaxelprodrug reduce the apoptosis index of tumor cells. (B) Micrographsdemonstrate the reduced apoptosis after exposure to an αvβ3 targetedparticle comprising docetaxel. Apoptosis index equals the TUNEL positivearea divided by the methyl green nuclear positive only area.

FIG. 26A-B depicts (A) the structure of the myc drug, and (B) graphsillustrating the effect of myc drug on the proliferation of MultipleMyeloma cell lines i. H-929 ii. LP-1 iii. KMS-11 iv. UTMC-2 incubatedwith different concentrations of the myc-drug compared to the controlcontaining corresponding volumes of DMSO using Trypan Blue Exclusion.

FIG. 27A-B depicts graphs illustrating that a myc-max antagonist prodruginhibits melanoma proliferation in vitro at (A) 48 hrs and (B) 72 hrs.Tg: targeted; PFC: perfluorocarbon particles; tween: polysorbatemicelles.

FIG. 28 depicts a graph illustrating that αvβ3 targeted myc-prodrug PFCnanoparticles reduces SMC proliferation at 48 hours.

FIG. 29 depicts an illustration of a polysorbate micelle.

FIG. 30 depicts an illustration of a tapping mode AFM image of aqueousdispersion of nanocelle drop deposited over a glass surface.

FIG. 31 depicts a prodrug comprising methyl prednisolone.

FIG. 32A-B depicts a prodrug comprising camptothecin (A) and a schemefor synthesizing a campothecin prodrug (B).

FIG. 33A-B depicts two prodrugs comprising PNA.

FIG. 34 depicts a scheme for creating fumagillin analogues.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides one or more prodrug compositions,particles comprising one or more prodrugs, and methods of use thereof.Advantageously, the invention provides compositions and methods for invivo delivery of a compound to a target cell.

In one aspect, the present invention encompasses a drug delivery systemthat comprises a prodrug (described in section I below) embedded in anon-liposomal nanoparticle (described in Section II below). Thenanoparticle may further optionally comprise a homing ligand asdescribed herein. The drug delivery system allows intracellular deliveryof the prodrug while protecting the prodrug from physiologicalconditions that may inactive the drug.

I. Prodrug Composition

Generally speaking, a prodrug of the invention encompasses a compoundlinked to an acyl moiety of a phosphoglyceride. Suitablephosphoglycerides may include phosphatidyl choline, phosphatidylethanolamine, phosphatidyl inositol, and phosphatidyl serine. A compoundmay be linked to either position in a phosphoglyceride. For instance, acompound may be linked to the sn1 position or the sn2 position of aphosphoglyceride. In a preferred embodiment, the compound is linked tothe sn2 position.

(a) Suitable Compounds

Generally speaking a suitable compound of the invention is less than3000 da. In one embodiment, a compound is less than about 3000, 2900,2800, 2700, 2600, 2500, 2400, 2300, 2200, 2100, 2000, 1900, 1800, 1700,1600, 1500, 1400, 1300, 1200, 1100, 1000, 900, 800, 700, 600, 500, 400,300, 200, or 100 da. In another embodiment, a compound is between about2500 da and about 200 da. In yet another embodiment, a compound isbetween about 2000 da and about 200 da. In some embodiments, a compoundmay be larger than 3000 da, as long as the prodrug comprising thecompound maintains the ability to transfer from the outer leaflet of acell membrane to the inner leaflet of a cell membrane.

Typically, a suitable compound comprises a reactive group outside theactive site of the compound. This reactive site allows the linkage ofthe compound to the glyceride backbone as described below. A suitablecompound of the invention may typically be selected from the groupcomprising a small molecule, a metal atom, an organometallic complex, aradioactive compound, an amino acid polymer (e.g. a protein, a peptide,etc.), a carbohydrate, a lipid, a nucleic acid polymer, or a combinationthereof. Generally speaking, a suitable compound may be linked to aphosphoglyceride as described herein. Once the compound is cleaved fromthe glyceride backbone, the released form may be an active compound or apre-active compound. A compound may be derivatized to enhance a desiredproperty of the compound. Methods for derivatizing a compound are knownin the art.

In some embodiments, for instance, a compound may be a drug, atherapeutic compound, a steroid, a nucleic acid based material, orderivatives, analogues, or combinations thereof, in their native form orderivatized with hydrophobic or charged moieties to enhanceincorporation or adsorption to a nanoparticle. Such compounds may bewater soluble or may be hydrophobic. Non-limiting examples of compoundsmay include immune-related agents, thyroid agents, respiratory products,antineoplastic agents, anti-helmintics, anti-malarials, mitoticinhibitors, hormones, anti-protozoans, anti-tuberculars, cardiovascularproducts, blood products, biological response modifiers, anti-fungalagents, vitamins, peptides, anti-allergic agents, anti-coagulationagents, circulatory drugs, metabolic potentiators, anti-virals,anti-anginals, antibiotics, anti-inflammatories, anti-rheumatics,narcotics, cardiac glycosides, neuromuscular blockers, sedatives, localanesthetics, general anesthetics, or radioactive atoms or ions. Incertain embodiments, a compound is an aptamer, or a nucleic acidderivative, such as peptide nucleic acid (PNA) or locked nucleic acid(LNA).

In an exemplary embodiment, the compound may be doxorubicin, paclitaxel,taxol, lenalidomide, methotrexate, bortezomib, a myc-inhibitor,lenalidomide, cis platin, methyl prednisolone, fumagillin, camptothecin,a peptide nucleic acid, a PDT drug, or a derivative or analogue thereofthat retains pharmaceutical activity. In one embodiment, the compoundmay be an analogue of fumagillin. In some embodiments, an analogue offumagillin is selected from the analogues detailed in Example 12. Inother embodiments, the compound may be a PDT drug, such as the prodrugof formula XI. Additional suitable PDT drugs are known in the art, andmay include porfimer sodium, aminolevulinic acid, and methyl ester ofaminolevulinic acid.

In other exemplary embodiments, the compound may be selected from acompound listed in Table A below.

TABLE A Non-limiting Examples of Compounds Category of compoundNon-limiting examples Immune-related immune serums, antitoxins,antivenoms agents bacterial vaccines, viral vaccines, rabies prophylaxisproducts thyroid agents iodine products and anti-thyroid agentsrespiratory xanthine derivatives theophylline and products aminophyllineantineoplastic platinum compounds (e.g., spiroplatin, agents cisplatin,and carboplatin), methotrexate, fluorouracil, adriamycin, mitomycin,ansamitocin, bleomycin, cytosine arabinoside, arabinosyl adenine,mercaptopolylysine, vincristine, busulfan, chlorambucil, melphalan(e.g., PAM, L-PAM or phenylalanine mustard), mercaptopurine, mitotane,procarbazine hydrochloride dactinomycin (actinomycin D), daunorubicinhydrochloride, doxorubicin hydrochloride, paclitaxel and other taxanes,rapamycin, manumycin A, TNP-470, plicamycin (mithramycin),aminoglutethimide, estramustine phosphate sodium, flutamide, leuprolideacetate, megestrol acetate, tamoxifen citrate, testolactone, trilostane,amsacrine (m-AMSA), asparaginase (L- asparaginase) Erwina asparaginase,interferon α-2a, interferon α-2b, teniposide (VM-26), vinblastinesulfate (VLB), vincristine sulfate, bleomycin sulfate, hydroxyurea,procarbazine, and dacarbazine anti-helmintics pyrantel pamoate,piperazine, tetrachloroethylene, thiabendazole, niclosamideantimalarials Chloroquine, amodiaquine, antifolate drugs, proguanil(chloroguanide), mefloquine, quinine, halofantrine, artemesinin andderivaties, primaquine, doxycycline, tetracycline, and clindamycinmitotic inhibitors etoposide, colchicine, and the vinca alkaloidshormones androgens, progestins, estrogens and antiestrogens, growthhormone, melanocyte stimulating hormone, estradiol, beclomethasonedipropionate, betamethasone, betamethasone acetate and betamethasonesodium phosphate, vetamethasone disodium phosphate, vetamethasone sodiumphosphate, cortisone acetate, dexamethasone, dexamethasone acetate,dexamethasone sodium phosphate, flunisolide, hydrocortisone,hydrocortisone acetate, hydrocortisone cypionate, hydrocortisone sodiumphosphate, hydrocortisone sodium succinate, methylprednisolone,methylprednisolone acetate, methylprednisolone sodium succinate,paramethasone acetate, prednisolone, prednisolone acetate, prednisolonesodium phosphate, prednisolone tebutate, prednisone, triamcinolone,triamcinolone acetonide, triamcinolone diacetate, triamcinolonehexacetonide, fludrocortisone acetate, oxytocin, vassopressin, glucagonand their derivatives antiprotozoans chloroquine, hydroxychloroquine,metronidazole, quinine and meglumine antimonite antitubercularspara-aminosalicylic acid, isoniazid, capreomycin sulfate cycloserine,ethambutol hydrochloride ethionamide, pyrazinamide, rifampin, andstreptomycin sulfate cardiovascular chelating agents and mercurialdiuretics and products cardiac glycosides blood products parenteraliron, hemin, hematoporphyrins and their derivatives biologicalmuramyldipeptide, muramyltripeptide, response modifiers microbial cellwall components, lymphokines (e.g., bacterial endotoxin such aslipopolysaccharide, macrophage activation factor), sub-units of bacteria(such as Mycobacteria, Corynebacteria), the synthetic dipeptideN-acetyl-muramyl-L-alanyl-D- isoglutamine anti-fungal agentsketoconazole, nystatin, griseofulvin, flucytosine (5-fc), miconazole,amphotericin B, ricin, cyclosporins, and β-lactam antibiotics (e.g.,sulfazecin) vitamins cyanocobalamin neinoic acid, retinoids andderivatives such as retinol palmitate, and α- tocopherol peptidesmanganese super oxide dismutase; enzymes such as alkaline phosphataseanti-allergic agents Amelexanox anti-coagulation phenprocoumon andheparin agents circulatory drugs Propranolol metabolic Glutathionepotentiators antivirals acyclovir, amantadine azidothymidine (AZT, DDI,Foscarnet, or Zidovudine), ribavirin and vidarabine monohydrate (adeninearabinoside, ara-A) antianginals diltiazem, nifedipine, verapamil,erythritol tetranitrate, isosorbide dinitrate, nitroglycerin (glyceryltrinitrate) and pentaerythritol tetranitrate antibiotics dapsone,chloramphenicol, neomycin, cefaclor, cefadroxil, cephalexin, cephradineerythromycin, clindamycin, lincomycin, amoxicillin, ampicillin,bacampicillin, carbenicillin, dicloxacillin, cyclacillin, picloxacillin,hetacillin, methicillin, nafcillin, oxacillin, penicillin includingpenicillin G and penicillin V, ticarcillin rifampin, aminoglycosides andtetracycline antiinflammatories diflunisal, ibuprofen, indomethacin,meclofenamate, mefenamic acid, naproxen, oxyphenbutazone,phenylbutazone, piroxicam, sulindac, tolmetin, aspirin and salicylatesantirheumatics Adalimumab, azathioprine, chloroquine andhydroxychloroquine (antimalarials), cyclosporine (Cyclosporin A),D-penicillamine, etanercept, gold salts (sodium aurothiomalate,auranofin), infliximab, leflunomide, methotrexate, minocycline (atetracycline antibiotic), sulfasalazine narcotics Paregoric, opiates,codeine, heroin, methadone, morphine and opium cardiac glycosidesdeslanoside, digitoxin, digoxin, digitalin and digitalis neuromuscularatracurium mesylate, gallamine triethiodide, blockers hexafluoreniumbromide, metocurine iodide, pancuronium bromide, succinylcholinechloride (suxamethonium chloride), tubocurarine chloride and vecuroniumbromide sedatives amobarbital, amobarbital sodium, (hypnotics)aprobarbital, butabarbital sodium, chloral hydrate, ethchlorvynol,ethinamate, flurazepam hydrochloride, glutethimide, methotrimeprazinehydrochloride, methyprylon, midazolam hydrochloride, paraldehyde,pentobarbital, pentobarbital sodium, phenobarbital sodium, secobarbitalsodium, talbutal, temazepam and triazolam local anesthetics bupivacainehydrochloride, chloroprocaine hydrochloride, etidocaine hydrochloride,lidocaine hydrochloride, mepivacaine hydrochloride, procainehydrochloride and tetracaine hydrochloride general droperidol,etomidate, fentanyl citrate with anesthetics droperidol, ketaminehydrochloride, methohexital sodium and thiopental sodium radioactivestrontium, iodide rhenium, yttrium, and particles or ionsradiopharmaceuticals, such as radioactive iodine and phosphorus product

(b) Linkage

A prodrug of the invention encompasses a compound, as defined in section1(a) above, linked to a phosphoglyceride. The linkage between theglyceride backbone and the compound may be any suitable linkage known inthe art. In exemplary embodiments, suitable linkages may comprisecarbon, oxygen, nitrogen, or a combination thereof.

The linkage may comprise at least one, two, three, four, five, six,seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen,sixteen, seventeen, eighteen, nineteen, twenty, or more than twentyatoms, counted from the glyceride backbone. In an exemplary embodiment,the linkage comprises at least five atoms, counted from the glyceridebackbone.

Generally speaking, the linkage is selected so that the sn2 position ofthe glyceride backbone is cleavable by an enzyme. Typically, such anenzyme may be found intracellularly.

In addition, the linkage itself may be enzyme cleavable. In an exemplaryembodiment, the linkage may be cleaved by an intracellular enzyme. Inseveral embodiments, either the glyceride sn2 position or the linkagemay be cleaved by a lipase. For instance, in one embodiment the lipasemay be a phospholipid A₂ lipase (also known as phospholipase A₂). Inanother embodiment, the lipase may be a phospholipid A₁ lipase (alsoknown as phospholipase A₁). In yet another embodiment, the lipase may bea phospholipase B enzyme. In each of the above embodiments, the enzymeis capable of cleaving the linkage and thereby releasing the compoundfrom the linkage.

(c) Released Form of a Compound

When a prodrug of the invention is cleaved from the glyceride backbone,a released form of a compound is created. The released form may eitherbe an active compound or a pre-active compound. As used herein, an“active compound” is a compound that exerts a pharmaceutical effect onthe cell. Such an active compound may comprise the linkage defined insection 1(b) above, or a portion thereof. An “active compound” may alsobe a metabolite of the compound used to create the prodrug.

A pre-active compound, as used herein, is a compound that requiresenzyme activation to become an active compound as defined above. Forinstance, a pre-active compound of the invention may comprise a compounddefined in section 1(a) above and a linkage defined in section 1(b)above, or a portion thereof. The linkage may comprise an enzymerecognition site within the linkage, or between the linkage and thecompound. Generally speaking, an enzyme binds to the enzyme recognitionsite and cleaves the linkage, such that the linkage, or a portionthereof, is removed from the pre-active compound to produce an activecompound, as defined above. In an alternative embodiment, the activecompound may be metabolite of the pre-active compound.

(d) Nanoparticle Comprising a Prodrug

In exemplary embodiments of the application, a prodrug is included in ananoparticle. In such embodiments, the prodrug is substantially notreleased from the nanoparticle until after the fusion of thenanoparticle with the target cell membrane. In an exemplary embodiment,the prodrug is substantially not released from the nanoparticle untilafter the fusion of the nanoparticle with the outer leaflet of a targetcell membrane. Such fusion is described in more detail below. Briefly,however, the fusion of a nanoparticle with a target cell membrane allowslipid transfer between the nanoparticle and the target cell membrane.For example, in some instances, the lipid membrane of a nanoparticle mayfuse with the outer leaflet of the lipid membrane of a target cellmembrane, allowing transfer of nanoparticle derived lipids and/or aprodrug to the target cell membrane.

After fusion and the subsequent transfer of the prodrug from thenanoparticle to the target cell, the prodrug may be cleaved, detachingthe released form of the compound from the glyceride backbone. Generallyspeaking, this cleavage occurs after transfer of the prodrug from theouter leaflet of the target cell membrane to the inner leaflet. Thisresults in the compound being substantially released intracellularly.The released compound may comprise the linkage or a portion thereof asdescribed above. For more details, see section II below and theexamples.

(e) Exemplary Examples

In an exemplary embodiment, a prodrug of the invention comprises aprodrug of formula I, II, III, IV, V, VI, VII, VIII, IX, X, XI, XII,XIII, XIV, XV, XVI, XVII, XVIII or XIX. In another exemplary embodiment,a prodrug of the invention comprises a prodrug consisting of formula I,II, III, IV, V, VI, VII, VIII, IX, X, XI, XII, XIII, XIV, XV, XVI, XVII,XVIII or XIX. In yet another exemplary embodiment, a prodrug of theinvention comprises a prodrug of formula I, II, III, IV, V, VI, VII,VIII, IX, X, XI, XII, XIII, XIV, XV, XVI, XVII, XVIII or XIX, whereinthe compound is further derivatized in a manner that does notsignificantly alter the function of the prodrug. In still anotherexemplary embodiment, a prodrug of the invention comprises a prodrug offormula I, II, III, IV, V, VI, VII, VIII, IX, X, XI, XII, XIII, XIV, XV,XVI, XVII, XVIII or XIX, wherein the phosphoglyceride backbone isfurther derivatized in a manner that does not significantly alter thefunction of the prodrug.

In each of the above exemplary embodiments, a prodrug of formula I, II,III, IV, V, VI, VII, VIII, IX, X, XI, XII, XIII, XIV, XV, XVI, XVII,XVIII or XIX may have a linkage between the glyceride backbone and thecompound that may vary in the number of atoms represented in theformula. For instance, the linkage may be 1, 2, 3, 4, 5, 6, 7, or morethan 7 atoms in length for formulas I, II, III, IV, V, VI, VII, VIII,IX, X, XI, XII, XIII, XIV, XV, XVI, XVII, XVIII or XIX.

TABLE B Exemplary prodrugs Form- ula No. Structure I

II

III

IV

V

VI

VII

VIII

IX

X

XI

XII

XIII

XIV

XV

XVI

XVII

XVIII

XIX

II. Nanoparticle

A nanoparticle of the invention comprises a prodrug, as discussed insection I above, and an amphiphilic membrane. In some embodiments, theamphiphilic membrane comprises a prodrug. The membrane is stable in vivofor at least the time required for the particle to fuse with a targetcell membrane, and transfer the prodrug to the target cell membrane.

Advantageously, a nanoparticle of the invention may protect a highlylabile compound from in vivo inactivation. This is due, in part, to thesequestration of the compound, in the form of a prodrug, in theamphiphilic membrane. The membrane protects the compound from hydrolysisand from inactivation due to physiological conditions, such as pH orenzyme cleavage. This allows the delivery of an active compound to acell, extending the half-life of a compound in vivo, thereby enhancingthe pharmacokinetic and pharmacodynamic properties of the compound. As aresult, a compound with little previous in vivo efficacy may become aviable in vivo treatment option when formulated as a prodrug andincorporated in a nanoparticle described herein.

Usually, a nanoparticle of the invention may be about 10 nm to about 10μm. In some embodiments, a nanoparticle may be about 10, 20, 30, 40, 50,60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200,210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340,350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480,490, 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600, 610, 620,630, 640, 650, 660, 670, 680, 690, 700, 710, 720, 730, 740, 750, 760,770, 780, 790, 800, 810, 820, 830, 840, 850, 860, 870, 880, 890, 900,910, 920, 930, 940, 950, 960, 970, 980, 990, or 1000 nm. In otherembodiments, a nanoparticle may be about 1, 1.25, 1.5, 1.75, 2, 2.25,2.5, 2.75, 3, 3.25, 3.5, 3.75, 4, 4.25, 4.5, 4.75, 5, 5.25, 5.5, 5.75,or 6 μm. In yet another embodiment, a nanoparticle of the invention maybe less than 100 nm. In still another embodiment, a nanoparticle may beless than 200 nm.

(a) Nanoparticle Amphiphilic Membrane

A nanoparticle of the invention comprises an amphiphilic membrane.Generally speaking, the amphiphilic membrane may be comprised of between100% and 50% of an amphiphilic lipid, e.g. a phospholipid. In someembodiments, the membrane is comprised of about 100, 99, 98, 97, 96, 95,94, 93, 92, 91, 90, 89, 88, 87, 86, 85, 84, 83, 82, 81, 80, 79, 78, 77,76, 75, 74, 73, 72, 71, 70, 69, 68, 67, 66, 65, 64, 63, 62, 61, 60, 59,58, 57, 56, 55, 54, 53, 52, 51, or 50% phospholipid.

The composition of the amphiphilic membrane can vary, but typicallycomprises between about 0.1% to about 75% of a prodrug discussed insection I above. In one embodiment, the lipid membrane of a nanoparticlecomprises about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1% of aprodrug. In another embodiment, the lipid membrane of a nanoparticlecomprises about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34,35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52,53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70,71, 72, 73, 74, or 75 percent of a prodrug. In some embodiments, thelipid membrane of a nanoparticle comprises about 10% to about 60% of aprodrug. In other embodiments, the lipid membrane of a nanoparticlecomprises about 20% to about 50% of a prodrug. In yet anotherembodiment, the lipid membrane of a nanoparticle comprises about 30% toabout 40% of a prodrug.

A nanoparticle lipid membrane may comprise one or more than one type ofprodrug. For instance, a nanoparticle lipid membrane may comprise one,two, three, four, five, six, or more than six types of prodrug. In eachinstance, the total percent of the membrane that comprises prodrug willtypically be about 0.1% to about 70%.

Typically, the stable membrane of a nanoparticle of the invention shouldbe compatible with in vivo use. For example, the lipid membrane of ananoparticle should not substantially initiate the complement pathway orhemolysis.

The composition of a stable membrane can vary so long as a prodrug issubstantially not released from the particle until after the fusion ofthe particle with a target cell membrane, and the prodrug can betransferred from the nanoparticle lipid membrane to a target cellmembrane. An amphiphilic membrane may comprise polymers or a combinationof lipids and polymers. In one embodiment, the stable membrane comprisesamphiphilic material. The phrase “amphiphilic material,” as used herein,refers to a material that has both a hydrophobic and a hydrophilicportion, such as lipid material or amphiphilic polymers. The amphiphilicmaterial may be natural, synthetic, or semisynthetic. As used herein,“natural” refers to a material that may be found in nature, “synthetic”refers to a material that may be created in a laboratory setting, and“semisynthetic” refers to a natural material that has been altered in alaboratory setting. In one embodiment, the amphiphilic material is lipidmaterial. For instance, the outer layer may be a single lipid layer ormay include a multi-lamellar lipid layer. Lipid material is used hereinin its broadest sense, including but not limited to a derivatized,natural, or synthetic phospholipid, a fatty acid, cholesterol,lysolipid, lipid, sphingomyelin, tocopherol, glucolipid, sterylamine,cardiolipin, plasmalogen, lipid with ether or ester linked fatty acids,a polymerized lipid, lipoprotein, glycolipids, derivatized surfactants,drug functionalized lipids, targeted ligand functionalized lipids,contrast agents conjugated lipids, lipid polymers, surfactants, or acombination thereof.

The amphiphilic membrane may also include lipid-conjugated polyethyleneglycol (PEG). Generally speaking, however, the membrane does notcomprise more than 10% PEG. In some embodiments, the membrane comprisesless than 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1% of PEG.

Additionally, the stable membrane may comprise a surfactant. In someembodiments, preferred surfactants are phospholipids and cholesterol.Moreover, surfactants may include but are not limited to,1,2-dipalmitoyl-snglycerol-3-phosphoethanolamine-N-4-(p-maleimidophenyl)butyramide,amine-PEG₂₀₀₀-phosphatidylethanolamine, phosphatidylethanolamine,acacia, cholesterol, diethanolamine, glyceryl monostearate, lanolinalcohols, lecithin, including egg-yolk lecithin, mono- anddi-glycerides, mono-ethanolamine, oleic acid, oleyl alcohol, poloxamer,peanut oil, palmitic acid, polyoxyethylene 50 stearate, polyoxyl 35castor oil, polyoxyl 10 oleyl ether, polyoxyl 20 cetostearyl ether,polyoxyl 40 stearate, polysorbate 20, polysorbate 40, polysorbate 60,polysorbate 80, propylene glycol diacetate, propylene glycolmonostearate, sodium lauryl sulfate, sodium stearate, sorbitanmono-laurate, sorbitan monooleate, sorbitan mono-palmitate, sorbitanmonostearate, stearic acid, trolamine, and emulsifying wax. The abovesurfactants may be used alone or in combination to assist in stabilizingthe nanoparticles.

In one embodiment, the amphiphilic membrane of the particle may comprisepolysorbate. For instance, the membrane may comprise between about 1 andabout 50% polysorbate. In certain embodiments, the membrane may compriseabout 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37,38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50% polysorbate.

Moreover, suspending and/or viscosity-increasing agents that may be usedinclude, but are not limited to, acacia, agar, alginic acid, aluminummono-stearate, bentonite, magma, carbomer 934P, carboxymethylcellulose,calcium and sodium and sodium 12, carrageenan, cellulose, dextrin,gelatin, guar gum, hydroxyethyl cellulose, hydroxypropylmethylcellulose, magnesium aluminum silicate, methylcellulose, pectin,polyethylene oxide, polyvinyl alcohol, povidone, propylene glycolalginate, silicon dioxide, sodium alginate, tragacanth, and xanthum gum.

In various embodiments, the amphiphilic material of the lipid membranemay be cross-linked to stabilize the nanoparticle. Such cross-linking,however, should still allow adequate lipid mobility to facilitatetransfer of a prodrug from a nanoparticle to a target cell membrane. Insome embodiments, the particles may be cross-linked on the surface ofthe outer layer. In other embodiments, the particles may be cross-linkedwithin the outer layer. The cross-linking may be chemical cross-linkingor photochemical cross-linking. Briefly, suitable cross-linkers willreact with one or more active groups of the outer layer. Cross-linkersmay be homobifunctional or heterobifunctional. Suitable chemicalcross-linkers may include glutaraldehyde, bis-carboxylic acid spacers,or bis-carboxylic acid-active esters. Additionally, the outer layer maybe chemically cross-linked using a bis-linker amine/acid by carbodiimidecoupling protocol. Alternatively, the particle may be cross-linked usinga click chemistry protocol. In still other embodiments,carbodiimde-coupling chemistry, acylation, active ester coupling, oralkylation may be used to cross-link the outer layer. In an exemplaryembodiment, the cross-linking is carbodiimide mediated. In someembodiments, EDC (also EDAC or EDCI, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride), a highly water soluble carbodiimide, isemployed in the 4.0-6.0 pH range to activate carboxyl groups for thecoupling of primary amines to yield amide bonds. To enhance the couplingefficiencies, EDC may be used in combination with N-hydroxysuccinimide(NHS) or sulfo-NHS. One of ordinary skill in the art would recognizethat a suitable cross-linker can and will vary depending on thecomposition of the particle and the intended use.

(b) Fusion

A nanoparticle of the invention may fuse with a target cell membrane. Asused herein, “fuse” refers to an aligning of the lipid membrane of ananoparticle with the lipid membrane of a target cell, such thatinteraction between the two membranes may occur. In an exemplaryembodiment, “fuse” refers to hemifusion of the particle membrane withthe outer leaflet of the target cell membrane. (Lanza, et al.Circulation 2002; 106:2842; Partlow et al. Biomaterials 2008; 29: 3367;Soman, et al. Nano Letters 2008; 8:1131-1136) In one embodiment, ananoparticle of the invention comprises a lipid membrane that is stable,in vivo, for at least the time required for the nanoparticle to fusewith a target cell membrane and transfer the prodrug to the target cellmembrane. Stated another way, a nanoparticle of the inventionsubstantially retains the prodrug within the lipid membrane of thenanoparticle unless and until the nanoparticle fuses with a target cellmembrane and transfers the prodrug from the nanoparticle to the targetcell membrane. In another embodiment, a nanoparticle of the inventioncomprises a lipid membrane that is stable, in vivo, for at least thetime required for the nanoparticle to fuse with a target cell membraneto enable endocytosis of the nanoparticle.

The length of time required for a nanoparticle to fuse with a targetcell membrane can and will vary depending on the nanoparticle (e.g.whether it comprises a homing ligand), the size of the nanoparticle, thelocation of the intended target cell, and the prodrug utilized, amongother factors. One of skill in the art would be able to perform assaysknown in the art to determine the ideal length of time required for aparticle nanoparticle/prodrug/target cell combination.

In some embodiments, the length of time is 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 minutes. In otherembodiments, the length of time is 20, 21, 22, 23, 24, 25, 26, 27, 28,29, 30, or more than 30 minutes. For instance, the length of time may beabout 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, ormore than 100 minutes. In an exemplary embodiment, the length of time isapproximately 20 minutes.

(c) Transfer of the Prodrug

As briefly mentioned above, a prodrug of the invention may betransferred from the lipid membrane of a nanoparticle to the lipidmembrane of a cell. In certain embodiments, to enable transfer of theprodrug, the lipid membrane of the nanoparticle must be mobile.Furthermore, in certain embodiments, the lipids of the nanoparticlelipid membrane must be free to exchange with the target cell lipidmembrane. Stated another way, in these embodiments, a nanoparticle lipidmembrane should not have substantial surface barriers or energy barriersto lipid exchange with a target cell membrane. This may, for instance,impact the lipid composition of the nanoparticle lipid membrane. Lipidcompositions may be tested using methods known in the art to ensureadequate lipid mobility to transfer the prodrug from a nanoparticle to atarget cell membrane. In an exemplary embodiment, as shown in theexamples, the membrane of the particle forms a hemifusion structure withthe outer leaflet of the target cell membrane. Such a fusion event maybe visualized, as illustrated in the examples. Hence, one of skill inthe art would be able to determine if a particular membrane, formedusing the guidelines detailed above, forms a hemifusion structure with atarget cell membrane.

The amount of time required for transfer of a prodrug from the membraneof a nanoparticle to the lipid membrane of a target cell can and willvary depending on several factors, including the nanoparticle (e.g.whether it comprises a homing ligand), the size of the nanoparticle, thelocation of the intended target cell, and the prodrug utilized, amongother factors. In some embodiments, the length of time is 1, 2, 3, 4, 5,6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 minutes. Inother embodiments, the length of time is 20, 21, 22, 23, 24, 25, 26, 27,28, 29, 30, or more than 30 minutes. For instance, the length of timemay be about 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95,100, or more than 100 minutes.

(d) Homing Ligand

In some embodiments, a nanoparticle of the invention may comprise ahoming ligand. As used herein, “homing ligand” refers to a biomoleculethat aids the fusion of the nanoparticle with the target cell membrane.

Homing ligands may include, but are not limited to, antibodies, antibodyfragments, proteins, peptides, carbohydrates, lipids, small molecules,polysaccharides, nucleic acids, aptamers, peptidomimetics, othermimetics and drugs alone or in combination. Additionally, homing ligandsmay include microbes, such as phage or viruses. A homing ligand may alsobe an engineered analogue or derivative of each of the above. Homingligands may be may be attached directly or indirectly to thenanoparticle.

Direct conjugation of a homing ligand to a nanoparticle refers to thepreparation of a homing ligand-particle complex wherein the homingligand is either adsorbed through ionic, electrostatic, hydrophobic orother noncovalent means to the nanoparticle surface (e.g.acylated-antibody, or hybridization between complementary nucleic acidsequences), or chemically linked to the surface through covalent bondsto a component of the lipid surface, or intrinsically incorporated intothe lipid membrane as a component of the membrane (e.g. a lipidderivatized to a peptidomimetic agent).

Indirect conjugation refers to forming the complex between thenanoparticle and the homing ligand in vivo in two or more steps.Indirect conjugation utilizes a chemical linking system to produce theclose and specific fusion of the particle to a targeted cell or tissuesurface. A non-limiting example of an indirect homing system isavidin-biotin.

Avidin-biotin interactions are useful noncovalent homing systems thathave been incorporated into many biological and analytical systems andselected in vivo applications. Avidin has a high affinity for biotin(10⁻¹⁵ M) facilitating rapid and stable binding under physiologicalconditions. Homing systems utilizing this approach are administered intwo or three steps, depending on the formulation. Typically, abiotinylated ligand, such as a monoclonal antibody, is administeredfirst and is “pre-homed” to a unique molecular epitope. Next, avidin isadministered, which binds to the biotin moiety of the “pre-homed”ligand. Finally, the biotinylated particle is added and binds to theunoccupied biotin-binding sites remaining on the avidin therebycompleting the biotinylated ligand-avidin-particle “sandwich”. Theavidin-biotin approach can avoid accelerated, premature clearance ofhomed particles by the mononuclear phagocyte system (MPS) secondary tothe presence of surface antibody. Additionally, avidin, with fourindependent biotin-binding sites provides signal amplification andimproves detection sensitivity.

Homing ligands may be chemically attached to the surface of particles bya variety of methods depending upon the nature of the homing ligand andcomposition of the particle surface. Direct chemical conjugation ofhoming ligands to proteinaceous particles often take advantage ofnumerous amino-groups (e.g. lysine) inherently present within thesurface. Alternatively, functionally active chemical groups such aspyridyldithiopropionate, maleimide or aldehyde may be incorporated intothe surface as chemical “hooks” for homing ligand conjugation after theparticles are formed. Another common post-processing approach is toactivate surface carboxylates with carbodiimide prior to homing ligandaddition.

The selected covalent linking strategy is primarily determined by thechemical nature of the homing ligand. For instance, monoclonalantibodies and other large proteins may denature under harsh processingconditions whereas the bioactivity of carbohydrates, short peptides,aptamers, drugs or peptidomimetics often can be preserved under theseconditions.

To ensure high homing ligand binding integrity and maximize nanoparticleavidity, flexible spacer arms, e.g. polyethylene glycol, amino acids,long or short chain hydrocarbons, sugars (e.g. polydextrose), nucleicacids, aptamers, or simple caproate bridges, can be inserted between anactivated surface functional group and the homing ligand. Theseextensions may be 2 nm or longer.

The homing ligand may be immobilized within the lipid material by usinga “primer material”. A “primer material” is any surfactant compatiblecompound incorporated in the particle to chemically couple with oradsorb a specific binding or homing ligand i.e. any constituent orderivatized constituent incorporated into the lipid membrane that couldbe chemically utilized to form a covalent bond between the particle andhoming ligand or a component of the homing ligand (if it has subunits).The homing ligand may be covalently bonded to “primer material” withcoupling agents using methods that are known in the art. One type ofcoupling agent may use a carbodiimide such as 1-ethyl-3-(3-N,Ndimethylaminopropyl)carbodiimide hydrochloride or1-cyclohexyl-3-(2-morpholinoethyl)carbodiimidemethyl-p-toluenesulfonate. The primer material may beamine-PEG₂₀₀₀-phosphatidylethanolamine, phosphatidylethanolamine,N-caproylamine phosphatidylethanolarnine, N-dodecanylaminephosphatidylethanolamine, phosphotidylthioethanol,1,2-diacyl-sn-glycerol-3-phosphoethanolamine-N-[4-p-maleimidephenyl)-butyramide, N-succinyl-phosphatidylethanolamine,N-glutaryl-phosphatidylethanolamine,N-dodecanyl-phosphatidylethanolamine,N-biotinyl-phosphatidylethanolamine,N-biotinylcaproyl-phosphatidylethanolamine, and phosphatidylethyleneglycol. Other suitable coupling agents may include aldehyde couplingagents having either ethylenic unsaturation such as acrolein,methacrolein, or 2-butenal, or having a plurality of aldehyde groupssuch as glutaraldehyde, propanedial or butanedial. Other coupling agentsmay include 2-iminothiolane hydrochloride and bifunctionalN-hydroxysuccinimide esters such as disuccinimidyl substrate,disuccinimidyl tartrate, bis[2-(succinimidooxycarbonyloxy)ethyl]sulfone,disuccinimidyl propionate, and ethylene glycolbis(succinimidylsuccinate). Non-limiting examples of heterobifunctional reagents mayinclude N-(5-azido-2-nitrobenzoyloxy)succinimide, p-azidophenylbromide,p-azidophenylglyoxal, 4-fluoro-3-nitrophenylazide,N-hydroxysuccinimidyl-4-azidobenzoate, m-maleimidobenzoylN-hydroxysuccinimide ester, methyl-4-azidophenylglyoxal,4-fluoro-3-nitrophenyl azide, N-hydroxysuccinimidyl-4-azidobenzoatehydrochloride, p-nitrophenyl 2-diazo-3,3,3-trifluoropropionate,N-succinimidyl-6-(4′-azido-2′-nitrophenylamino)hexanoate, succinimidyl4-(N-maleimidomethyl)cyclohexane-1-carboxylate, succinimidyl4-(p-maleimidophenyl)butyrate,N-succinimidyl(4-azidophenyldithio)propionate, N-succinimidyl3-(2-pyridyldithio)propionate, and N-(4-azidophenylthio)phthalamide.Non-limiting examples of homobifunctional reagents may include1,5-difluoro-2,4-dinitrobenzene,4,4′-difluoro-3,3′-dinitrodiphenylsulfone,4,4′-diisothiocyano-2,2′-disulfonic acid stilbene,p-phenylenediisothiocyanate, carbonylbis(L-methionine p-nitrophenylester), 4,4′-dithiobisphenylazide, erythritolbiscarbonate andbifunctional imidoesters such as dimethyl adipimidate hydrochloride,dimethyl suberimidate, dimethyl 3,3′-dithiobispropionimidatehydrochloride and the like. Covalent bonding of a specific bindingspecies to the “primer material” can be carried out with the abovereagents by conventional, well-known reactions, for example, in theaqueous solutions at a neutral pH and at temperatures of less than 25°C. for 1 hour to overnight.

A particle membrane may generally comprise between 0% and about 3% of ahoming ligand. For instance, in one embodiment, a membrane may compriseup to 1% of a homing ligand, up to 2% of a homing ligand, or up to 3% ofa homing ligand.

(e) Passive Homing

As an alternative to a nanoparticle of the invention comprising a homingligand, a nanoparticle may use “passive homing.” As used herein,“passive homing” refers to the natural tendency of nanoparticles toaccumulate in, and therefore fuse with, target cell membranes of certaintissues. For instance, passive homing may refer to charge interactionsbetween a lipid membrane of a nanoparticle and the lipid membrane of atarget cell. Or, in other embodiments, passive homing may refer to theenhanced permeability effect found in tumor tissue.

(f) Nanoparticle Core

The core of a nanoparticle of the invention can and will vary withoutimpacting the necessary features of the lipid membrane. Generallyspeaking, however, the core should allow adequate lipid transfer betweenthe nanoparticle and the target cell membrane.

(g) Imaging/Tracking Agents

A nanoparticle of the invention may also include other imaging/trackingagents. For instance, a nanoparticle may include imaging/tracking agentsthat may be used for microscopy, e.g. fluorescent microscopy, confocalmicroscopy, or electron microscopy, magnetic resonance imaging,tomography, gamma (SPECT/CT, planar) and positron emission tomography(PET/CT), radiography, computed tomography (CT), spectral CT,photoacoustic tomography (PAT) or ultrasound. Imaging/tracking agentsmay be detectable in situ, in vivo, ex vivo, and in vitro. Microscopyimaging/tracking agents are well known in the art, and may includefluorescent molecules such as FITC, rhodamine, and Alexafluor cyan dyes.Similarly, magnetic resonance imaging molecules, such as paramagneticand superparamagnetic agents, radiography imaging molecules, nearinfrared (NIR) optical agents and ultrasound molecules are well known inthe art, and an appropriate imaging molecule may be selected by one ofskill in the art after consideration of the composition of the particleand the intended use of the particle. In certain embodiments, the outerlayer may also comprise chelators for radiometals to be detected bynuclear imaging methods, such as PET, SPECT, and related methodologies.

(h) Pharmaceutical Composition

The present invention further comprises a pharmaceutical compositioncomprising a nanoparticle, or a plurality of nanoparticles, of theinvention. A pharmaceutical composition may be a solution, a mixture, ora suspension of nanoparticles. In one embodiment, the pharmaceuticalcomposition may be a solution. In another embodiment, the pharmaceuticalcomposition may be a mixture. In another embodiment, the pharmaceuticalcomposition may be a suspension. A non-limiting example of a suspensionis a colloid.

In some embodiments, the pharmaceutical composition may be a colloid.Generally speaking a colloid is a suspension of fine particles that donot readily settle out of the suspension. A colloid may be formed bymicrofluidization.

A pharmaceutical composition of the particles of the invention may beadministered to a subject to enable imaging and/or treatment ofbiological tissue. Suitable subjects may include, but are not limitedto, mammals, amphibians, reptiles, birds, fish, and insects.Non-limiting examples of mammals include humans, non-human primates, androdents.

The pharmaceutical composition may be formulated and administered to asubject by several different means that will deliver an effective dosefor treatment and/or imaging. Such compositions may generally beadministered parenteraly, intraperitoneally, intravascularly, orintrapulmonarily in dosage unit formulations containing conventionalnontoxic pharmaceutically acceptable carriers, adjuvants, excipients,and vehicles as desired. The term parenteral as used herein includestopical, subcutaneous, intravenous, intramuscular, intraperitoneal,intracystic, intrauterine, intraauricular, intranasal, ocular,intraocular, intrapulmonary, oral, intrapharyngeal, transrectal, intraor transurethral, intrauterine, intravaginal, or intrasternal injectionor infusion. Additionally, the term parenteral includes spraying oraerosol administration techniques. In one embodiment, the compositionmay be administered in a bolus. In a preferred embodiment, thecomposition may be administered intravenously. Formulation ofpharmaceutical compositions is discussed in, for example, Hoover, JohnE., Remington's Pharmaceutical Sciences, Mack Publishing Co., Easton,Pa. (1975), and Liberman, H. A. and Lachman, L., Eds., PharmaceuticalDosage Forms, Marcel Decker, New York, N.Y. (1980).

Injectable preparations, for example, sterile injectable aqueous oroleaginous suspensions, may be formulated according to the known artusing suitable dispersing or wetting agents and suspending agents. Thesterile injectable preparation may also be a sterile injectable solutionor suspension in a nontoxic parenterally acceptable diluent or solvent.Among the acceptable vehicles and solvents that may be employed arewater, Ringer's solution, and isotonic sodium chloride solution. Inaddition, sterile, fixed oils are conventionally employed as a solventor suspending medium. For this purpose, any bland fixed oil may beemployed, including synthetic mono- or diglycerides. In addition, fattyacids such as oleic acid are useful in the preparation of injectables.Dimethyl acetamide, surfactants including ionic and non-ionicdetergents, and polyethylene glycols can be used. Mixtures of solventsand wetting agents such as those discussed above are also useful. Forimaging purposes, formulations for parenteral administration may be inthe form of biocompatible solutions or suspensions. Other adjuvants andmodes of administration are well and widely known in the pharmaceuticalart.

One of skill in the art will recognize that the amount and concentrationof a pharmaceutical composition administered to a subject for treatmentand/or imaging will depend in part on the subject and the tissue to betreated and/or imaged. Methods for determining optimal amounts are knownin the art, and more details may be found in the Examples.

A pharmaceutical composition of the invention may further comprise anadditional pharmaceutically active compound known in the art.

III. Methods

Another aspect of the present invention encompasses methods of use for aprodrug or nanoparticle of the invention. Methods of the invention maygenerally be used in vitro, in vivo, or ex vivo.

In one embodiment, the present invention provides a method fordelivering a compound to a cell. The method comprises administering aprodrug of the invention to the cell. In an exemplary embodiment, themethod comprises administering a nanoparticle comprising a prodrug ofthe invention to the cell. In a further exemplary embodiment, the methodcomprises administering a targeted nanoparticle comprising a prodrug ofthe invention to the cell. Generally speaking, a suitable cell is anyeukaryotic cell, where the outer leaflet of the cell membrane is capableof forming a hemifusion structure with the membrane of the particle.

In another embodiment, the present invention provides a method forincreasing the half-life of a compound in the blood of a subject. Themethod comprises administering a prodrug of the invention to a subject.In an exemplary embodiment, the method comprises administering ananoparticle comprising a prodrug of the invention. Generally speaking,a suitable subject is a mammal. In one embodiment, a suitable subjectmay be a rodent. In another embodiment, a suitable subject may be anagricultural animal, e.g. a horse, cow, pig, chicken, etc. In yetanother embodiment, a suitable subject is a non-human primate. In stillyet another embodiment, a suitable subject is a human.

In yet another embodiment, the present invention provides a method fordecreasing the effective dose of a compound in a subject. The methodcomprises administering a prodrug of the invention to the subject. In anexemplary embodiment, the method comprises administering a nanoparticlecomprising a prodrug of the invention to the subject. Suitable subjectsare as defined above.

In still another embodiment, the present invention provides a method forcontrolling the release of a compound in a cell. The method comprisesadministering a prodrug of the invention to the cell. In an exemplaryembodiment, the method comprises administering a nanoparticle comprisinga prodrug of the invention to the cell. Suitable cells are as definedabove.

In a further embodiment, the present invention provides a method forinhibiting angiogenesis in a subject, the method comprisingadministering a prodrug of the invention to a subject, wherein theprodrug comprises an antiangiogenic compound. In an exemplaryembodiment, the method comprises administering a nanoparticle comprisinga prodrug comprising an antiangiogenic compound to a subject.

In an exemplary embodiment, the invention encompasses a method ofadministering a prodrug of formula I, II, III, IV, V, VI, VII, VIII, IX,X, XI, XII, XIII, XIV, XV, XVI, XVII, XVIII, or XIX to a cell. Themethod comprises administering a nanoparticle comprising a prodrug offormula I, II, III, IV, V, VI, VII, VIII, IX, X, XI, XII, XIII, XIV, XV,XVI, XVII, XVIII, or XIX to the cell.

The following examples are included to demonstrate preferred embodimentsof the invention. It should be appreciated by those of skill in the artthat the techniques disclosed in the examples that follow representtechniques discovered by the inventors to function well in the practiceof the invention. Those of skill in the art should, however, in light ofthe present disclosure, appreciate that may changes can be made in thespecific embodiments that are disclosed and still obtain a like orsimilar result without departing from the spirit and scope of theinvention, therefore all matter set forth or shown in the accompanyingdrawings is to be interpreted as illustrative and not in a limitingsense.

EXAMPLES

The following examples illustrate various iterations of the invention.

Example 1. Targeting and Efficacy of Doxorubicin Prodrug

Two examples of prodrug candidates using paclitaxel or doxorubicin,coupled to a phosphatidylcholine backbone with a 5-carbon sn-2 acylspacer were synthesized (See Examples below). The structures of thecompounds produced were characterized by 1H NMR (400 MHz) spectroscopy.The effect of the α_(v)β₃ integrin-targeted doxorubicin prodrug wastested in 2F2B mouse endothelial cells induced to express integrin.Doxorubicin prodrug transfer to the targeted cell and intracellulardistribution was confirmed using light microscopy (FIG. 1). Targeteddoxorubicin prodrug was distributed in the lipid membrane, throughoutthe cell membranes and in the nucleus, whereas free doxorubicin drug wasonly seen in the nucleus. Doxorubicin distribution in the cell membraneacts as a reservoir for doxorubicin transfer to the nucleus for a moreeffective treatment. The enzymatically released drug also elicited amarked inhibition of endothelial cell proliferation at a level greaterthan that elicited by free doxorubicin (FIG. 2).

Example 2. In Vivo Activity of Doxorubicin and Paclitaxel Prodrugs

Anti-angiogenesis treatment with integrin-targeted doxorubicin prodrugand paclitaxel prodrug PFC nanoparticles was demonstrated using an invivo Matrigel plug model in rats. The therapeutic response was assessedusing MRI neovascular mapping at 3T with α_(v)β₃ integrin-targetedparamagnetic PFC nanoparticles (FIG. 3). Angiogenesis was decreased byboth treatment formulations relative to control. Similar results wereobtained in vivo with the Vx2 tumor model in rabbits using paclitaxelprodrug (FIG. 4). Therefore, in contradistinction to prior research thatshowed loss of paclitaxel or doxorubicin during in vitro dissolution,the phospholipid prodrug forms were retained in circulation, deliveredto the target cell, released enzymatically and exerted the intendedantiproliferative effects.

Example 3. Synthesis of Sn-2 Doxorubicin Prodrug

More than three sites are available for functional modification ofdoxorubicin (FIG. 5): the side chain carbonyl group (site 1), the sidechain alcoholic group (site 2) and the amine functionality in the sugarmoiety (site 3). In this example, site-3 was used for the modificationsdescribed below.

PC-doxorubicin (PC-DXR) conjugate 1 was synthesized by reactingdoxorubicin with 16:0-09:0 ALDO (PC)(1-palmitoyl-2-(9′-oxo-nonanoyl)-sn-glycero-3-phosphocholine) inmethanol (anhydrous) in the presence of TFA. The subsequent formation ofimine was reduced by sodium cyanoborohydride to produce the finalproduct. The structure of the compound was characterized by 1H NMR (400MHz) spectroscopy (FIG. 7). The conceptual proof of this prodrugapproach was demonstrated microscopically by the intracellulardistribution doxorubicin, and the marked inhibition of endothelial cellproliferation produced by the enzymatically released drug described inExample 1 above.

Example 4. Synthesis of the Paclitaxel Prodrug

Paclitaxel prodrug was synthesized following a five-step synthesisprocess and purified by column chromatography (FIG. 8). Briefly,commercially available paclitaxel (Avachem Scientific, Inc.) was treatedwith succinic anhydride in the presence of pyridine to give 2′-succinylpaclitaxel. NHS ester (6) of this intermediate may be obtained byreaction with N-succinimidyl diphenylphosphate (SDPP). The ester wastreated with an excess of mono-Boc-ethylene diamine at low temperaturefollowed by deprotection of the tert-Boc. A flexible, linear diamine(1,3-diamino propane) was chosen to reduce the steric hindrance.Finally, the paclitaxel amine was subjected to reductive amination withALDO PC (or PE) to produce paclitaxel prodrugs (7).

Example 5. Testing of Sn-2 Paclitaxel Prodrug

2F2B mouse endothelial cells (ATCC, Manassas, Va., USA) were incubatedfor 2 days in media, upregulated with 10 nM nicotine or 10 μMangiotensin II to express α_(v)β₃ integrin. The cells may then beexposed to integrin-targeted versus nontargeted paclitaxel-GNBnanoparticle treatments with varying drug loads (0.5 to 5 mole %). Thecells were also exposed to equivalent amounts of free drug for 30minutes as a control. Unbound nanoparticles or unabsorbed drug waswashed from wells, and cultures were grown for 6 days, and attachedviable cell numbers were counted. The number of cells was significantlydecreased when treated with paclitaxel-PC prodrug nanoparticles(PC-PTXL), versus equivalent amounts of free Taxol, α_(v)β₃integrin-targeted nanoparticles alone, or saline (FIG. 9).

Example 6. Synthesis of Cis-Platinum Prodrugs

For the synthesis of platinum based anti cancer prodrugs, two approachesmay be followed. The first approach (FIG. 10) may involve thepreparation of an amine terminated cis platin (9) followed byconjugation with oxidized lipids. The coupling intermediate producedfrom the amidation reaction of compound 8 with mono Boc-ethylenediaminein presence of HATU/DIPEA, may be subjected to deprotection to producecompound 9. Compound 9 may undergo reductive amination with ALDO PC inmethanol to generate cis platin prodrug-1 (10).

A second approach (FIG. 11) may involve the synthesis of an analoguebearing hydrophobically modified chelating diamines. Cis-platinintermediate 16 may be obtained in three steps from compound 13.Intermediate 16 may be subjected to complexation with K₂PtCl₄ bymaintaining the pH of the resulting solution at pH 6-7. Finally,compound 13 may undergo reductive amination with ALDO (PC) or (PE) toproduce cis platin prodrug-2 (18).

Example 7. Synthesis of Methotrexate Prodrugs

The synthesis of the methotrexate conjugates is described in (FIG. 12).A short ethylene diamine spacer may be introduced between methotrexateand the oxidized lipid. 6-Bromomethyl-pteridine-2,4-diaminetrihydrobromide (BPT.HBr, 23) may be purchased from Ube Industries andcoupled with intermediate 24 to produce 25. Compound 25 may bedeprotected from tert-Boc followed by ester hydrolysis to produce amineterminated methotrexate (26). Reductive amination of 26 with ALDO (PE)or (PC) may be performed as described earlier to produce methotrexateprodrugs (27).

Example 8. Synthesis of Bortezomib Prodrug

The asymmetric synthesis of bortezomib-prodrug (FIG. 13) may involve thepreparation of intermediate-1 (N-sulfinyl α-amino boron pinacolatocomplex) by following published methods. Selective removal of theN-sufinyl group under mild acidic conditions may produce the aminehydrochloride (intermediate 2), which may then be coupled withN-Boc-L-phenylalanine by a TBTU/DIPEA mediated reaction protocol.Intermediate-3 (amine hydrochloride) may then undergo coupling with thecommercially available 3-aminopyrazine-2-carboxylic acid to produce thepinacol boronate of bortezomib. This may subsequently be hydrolyzedunder biphasic conditions utilizing iso-butylboronic acid as a pinacolsequestering agent. Finally the intermediate-4 may undergo a sodiumcyanoborohydride mediated reductive amination with ALDO (PC) in presenceof catalytic amounts of TFA to produce bortezomib prodrug.

Example 9. Synthesis and of MYC-Inhibitor Prodrugs

Myc-inhibitor-1 may be synthesized (FIG. 14) by reacting 4-ethylbenzaldehyde with rhodanine in the presence of a catalytic amount ofTween-80 in potassium carbonate solution at ambient temperature. Themixture may be neutralized with 5% HCl and the precipitant may betreated with saturated NaHSO₃ and re-crystallized with aqueous ethanol.This rhodanine derivative may be reacted to piperidine-mono-tert Boc andformaldehyde. Deprotection of the tert Boc in presence of TFA mayproduce the Myc-inhibitor-1. Finally Myc-inhibitor-1 may undergo sodiumcyano borohydride mediated reductive amination with ALDO (PC) inpresence of catalytic amounts of TFA to produce the Myc-rhodanineprodrug.

Example 10. Myc-Inhibitor Prodrug in Restenosis

Myc encodes a helix-loop-helix transcription factor upregulated in50-80% of human cancers and is associated with 100,000 US cancer deathsper year. Myc heterodimerizes with its partner Max to control targetgene transcription and is deeply integrated into the regulatory andcontrol mechanisms governing cell viability and proliferation. A recentestimate suggests that Myc binds to approximately 25,000 regions in thehuman genome. The loss of Myc proteins inhibits cell proliferation andgrowth, accelerates differentiation, increases cell adhesion, andaccentuates the response to DNA damage.

We believe that Myc is an ideal target for anti-cancer therapeutics,particularly MM in which it is highly overexpressed by selectivedisruptive interference of Myc-Max dimerization while permitting Myc-Madinteractions.

FIG. 28 illustrates that an αvβ3 targeted particle comprising a mycprodrug reduces SMC proliferation. Human coronary smooth muscle cellswere plated on cover slips (2500 cells) and incubated 2 hours. Eachtreatment was replicated 6 times. The intramural delivery of an αvβ3targeted particle comprising a myc prodrug, alone or with stents, offersan attractive new approach to restenosis.

Example 11. Synthesis of Lenalidomide Prodrugs

Lenalidomide is subjected to reductive amination in the presence of ALDO(PE) or (PC) in methanol (anhydrous) in the presence of catalyticamounts of TFA, followed by a one-pot reduction with NaCNBH₃ to producelenalidomide-prodrug (FIG. 15).

Example 12. Synthesis of Fumagillin Prodrugs

Synthesis of the initial prodrug (fumagillin prodrug 1) was accomplishedin a straightforward way by saponifying fumagillin to fumagilloldicyclohexylamine salt, which was then activated using DCC/DMAP mediatedcarbodiimide coupling protocol and then derivatized with oxidized lipid.

(3R,4S,5S,6R)-5-Methoxy-4-((2R,3R)-2-methyl-3-(3-methylbut-2-enyl)oxiran-2-yl)-1-oxaspiro[2.5]octan-6-ol,(Fumagillol, 2)

Fumagillin dicyclohexylamine salt (0.2 g, 0.31 mmol) was suspended in 2mL of 1:1 methanol:water and treated with 0.07 mL of 35% NaOH solution(0.62 mmol). The dark-brown mixture was stirred in an ice bath for 2 h,then warmed to room temperature and treated with another equivalent ofNaOH solution. The mixture was stirred until starting material was notdetected by TLC (□4 h); the methanol was evaporated and the residueextracted into ethyl acetate. The mixture was then extracted with κ%citric acid, brine, bicarbonate, and brine again, then dried with MgSO₄and concentrated in vacuo. The crude product was further purified bytreatment with activated charcoal in acetonitrile and filtration througha celite pad. Concentration yielded a colorless solid, 59 mg (70%). HRMSfound: MH+ (283.3).

General Procedure for the Preparation of Fumagillin Prodrug 1:

A solution of C16-09:0 (COOH) PC1-hexadecyl-2-azelaoyl-sn-glycero-3-phosphocholine (3.2 mmol) followedby DMAP (44 mg, 3.2 mmol) and DCC (46 mg, 3.2 mmol) were added to asolution of fumagillol (11 mg, 0.4 mmol) in dry dichloromethane (1 ml).The reaction mixture was stirred for overnight at room temperature thenthe mixture was passed over a short pad of silica gel usingEtOAc/n-hexane (1:2, v/v) and the filtered solvent was removed in vacuoto leave an oil residue that was purified by column chromatography onSiO2 with EtOAc/n-hexane (1:4, v/v) as elution solvent to give thefumagillin prodrug 1 compound as a pale yellowish solid. HR-MS found:991.5475 (M+2K−2H).

Other Strategies and Specific Examples

The challenge of this step will be to develop photo and chemicallyrobust analogs of fumagillin and its related candidates with improvedmembrane retention properties. One of the strategies would follow theremoval of unstable and pharmacologically inactive (and irrelevant)functionalities from their structures and introduce hydrophobicallysimilar moieties to the whole system. In the present invention, wedesign to substitute the all trans-decatetraenedioate with photostable,non-conjugated unsaturated chains. We will synthesize fumagillin analogsin which each of the potentially reactive epoxide groups will besubstituted either individually or in combination. The ester linkagewill be replaced by the incorporation of stable covalent bonds. Aparallel strategy would allow the incorporation of moieties that wouldprovide membrane adherence properties for these analogs. Thedecatetraenedioic tail will be substituted with hydrophobicallycomparable moieties. Synthetic methodologies for making fumagillinanalogs have been explored by several groups and disclosed in theliterature. We will develop efficient synthetic methodologies for theproposed analogs poised for further studies on detailed examination ofits biological activity with significant therapeutic potential. (SeeFIG. 34.)

Synthesis of Stable Fumagillin Prodrug

Fumagillin Prodrug 1:

Fumagillol (1) will be produced by the hydrolysis of fumagillin andsubjected to a DCC mediated coupling with commercially available PAzPC(16:0-9:0 COOH PC). The product will be recovered and immediately besubjected to reaction with LiCl in presence of acetic acid to open thespiro epoxide with chloro methyl functionality.

Fumagillin Prodrug 2:

Fumagillol will be activated with bis(4-nitrophenyl) carbonate followedby reacting with monoboc-ethylendimine to produce 6. In a typicalexperimental procedure, under a N₂ atmosphere, a mixture of fumagillol,bis(4-nitrophenyl) carbonate and DMAP in dry CH₂Cl₂ will be stirred for7 h. The reaction mixture will be diluted with CH₂Cl₂ and washed withH₂O. The organic layer will be dried (Na₂SO₄) and concentrated. Flashchromatography (EtOAc-hexane) will be used to yield the activatedfumagillol. Monoboc-protected ethylendiamine will then be coupled toprepare intermediate-6. The product will be recovered and immediately bereacted with LiCl in presence of acetic acid to open the spiro epoxidewith chloro methyl functionality. The boc will be deprotected with TFAand the product will be subjected to sodium cyano borohydride mediatedreductive amination in presence of the ALDO PC.

Synthesis of the Precursor Compounds:

Ovalicin (4) will be synthesized following a literature procedure byTakahashi et al.^(40a) A commercially available 2, 3:5,6-di-O-isopropylidene-R-D mannofuranose will be used as a startingmaterial to produce optically pure ovalicin in 10% overall yield.Fumagillol will be purchased from Sinova, Inc. and used as received.

Fumagillol will be subjected to oxidation using pyridinum chlorochromate(PCC)/pyridine to produce Fumaginone (3). In a typical experimentalprocedure, a mixture of fumagillol (1 equiv.), pyridinium chlorochromate(PCC, 8 equiv.) and pyridine (5 equiv.) in anhydrous CH₂Cl₂ is allowedto stir for 10 h at ambient temperature and the completion of thereaction is monitored by thin layer chromatography. The reaction mixtureis purified by silica gel column chromatography (EtOAc-CH₂Cl₂) to givefumaginone as clear oil.

Synthetic Analogs 1-2:

As briefly discussed above, in the present invention, we design tosubstitute the all trans-decatetraenedioate with photo stable,non-conjugated unsaturated chains (analog 1-2). Thus, analogs 1-2bearing a variety of non-conjugated substituent at the hydrophobic tailwill be prepared with either hydrogen (fumagillin series) or hydroxylgroup (ovalicin series). Briefly, the precursor compounds will besubjected to indium mediated organometallic allylation with respectivesubstituted allyl bromides.

Analogs 3-6:

Analog-3 can be synthesized from ovalicin-hydrazone. Briefly, ovalicin(or fumaginone) will be treated with LiCl in presence of acetic acid toopen the spiro epoxide with chloro methyl functionality. A solution ofovalicin in THF is stirred with LiCl and Acetic acid for 36 h and workedup by removal of THF, followed by addition of chloroform. The organiclayer is washed with H₂O, sodium bicarbonate, dried and purified bysilica chromatography (30% EtOAc-hexane).

This intermediate will be treated next with hydrazine under mild acidiccondition (acetic acid) to afford the corresponding hydrazone. Hydrazonewill then be subjected to selective reduction with sodium cyanoborohydride followed by DCC/DMAP mediated amidation in presence of therespective acid (E-isogeranic acid)^(40e) (Scheme 2). In the final step,spiro epoxide functionality will be optionally reformed. Analog 3 willbe treated with KOtBu in THF at 0° C. to afford analog-4 containingreformed spiro epoxide moiety.

In a separate pathway, intermediate-1 will be treated with hydroxylamine in presence of a mild acid to afford the corresponding oximederivative. The oxime derivative will be reduced, followed by aDCC-mediated esterification with E-isogeranic acid will produce analog5. 2,6-Octadienoic acid chloride may be also be used to esterify theoxime (analog 6).

E-isogeranic acid will be synthesized from E-isogeraniol by following aliterature report by Eustache and coworkers.^(40e) E-isogeraniol will besubjected to a chromium trioxide mediated oxidation in presence ofsulfuric acid in water and acetone mixture to afford the desiredE-isogeranic acid. The acid will be obtained in the pureenantioselective E-form and separated from byproducts by passing througha silica column. In a straightforward way, 2,6-Octadienoic acid,(2E,6E)—will be converted to acid chloride by treating it with PCl₅.⁴¹

Analog 7-9:

Based on a previous report by Liu et al,⁴² compounds carrying arotatable single bond between C10 and C20 carbons on the C4 side chainexhibited a reduced activity against MetAP-2 in comparison to analogswith rigid epoxide and diene side chains. Also a crystallographic dataindicated that that there was significant space within the pocket forfurther optimization.⁴² All together, we decided to replace the acidlabile side chain epoxide with a diene moiety.

In a typical experimental procedure, analog-5 will be treated with WCl₆in presence of n-BuLi at −78° C. followed by a KOtBu in THF at 0° C. toafford analogs 7 (scheme 3). Under argon atmosphere, n-BuLi is addeddropwise to a solution of WCl₆ in THF at −78° C. followed and allowed tostir for ½ h. A solution of analog-5 is added and allowed to react for 2h. NaOH is added to the reaction mixture and the product is extractedwith ether. The extracts were washed with NaOH, and water. The residuewas purified by column chromatography (ethyl acetate-hexane) to yieldanalog-7. Analogs 8-9 will be synthesized from analogs-4 and 6respectively by following the routes described above for the synthesisof analog-7.

Analogs 10-11:

We will also replace the exocyclic side chain epoxide with an oximefunctionality which may provide the desired geometry and substitutionpattern. Previous report by Pyun et al^(40m) showed that benzyloximebearing analogues exhibited excellent activities (˜1 nM in the MetAP-2assay.^(40m) A C4 oxime analog will be synthesized and evaluated. Theintermediate 3 can be easily synthesized from fumagillol as reportedpreviously by Fardis et al.^(40b) The intermediate-3 will be subjectedto ozonolysis at −78° C. followed by treatment with dimethyl sulphide toafford the corresponding keto derivative. The keto derivative will betreated with amino benzyl oxime (H₂N—OBn) in presence of TsOH andmolecular sieves (4 Å) to produce a mixture of E and Z benzyl oxime(intermediate 4). Intermediate-4 will then be oxidized to thecorresponding keto derivative. Treatment of intermediate-4 withhydrazine or hydroxyl amine will generate the corresponding oximederivative which will then be reduced and activated with DCC/DMAP toreact with E-isogeranic acid to produce analogs 10-11.

Analogs 12-15:

Fumarranol is a novel synthetic analog of fumagillin which has beenshown to selectively inhibits MetAP2 and endothelial cell proliferationwithout covalently binding MetAP-2.^(40g) Fumarranol consist of abicyclic ring structure with an opened up spiro epoxy moiety. We decidedto explore related fumarranol analogs along the strategy discussedabove. Analog-10 will be reacted with KOH to form a carbanion at theR-position of the 6-ketone group which undergoes an intramolecular SN2type reaction to open the spiro epoxide group (Diagram 4) to produce abicyclic ring structure (analog 12). Similarly, analogs 13-15 will besynthesized from analog 7 and 8 respectively.

Analogs 16-19:

We will also undertake the synthesis of analogs in which the spiro (C-3)epoxide will be opened with thiomethoxide (Scheme 5) functionality.Briefly, to a stirred solution of analog-7 in anhydrous DMF will beadded thiomethoxide at room temperature. The reaction mixture is stirredfor 2 h, then diluted with ethyl acetate and washed with saturatedaqueous NaHCO₃ and water. The organic phase is dried (anhydrous Na₂SO₄)and the residue is purified by column chromatography on silica gel(ethyl acetate:hexane) to produce analogs-16. Following a similarmethodology, analogs 17-19 will be synthesized starting from analog 8-9and 4 respectively.

Synthetic Analogs 20-25 (Fumagillin-PAF Analogs):

As described before, one of the challenges of this step will be todevelop new fumagillin analogs with improved membrane adherenceproperties. Towards this aim, a series of Fumagillin-PAF analogues alsotargeted at understanding the tolerability of MetAP2 toward substitutionat C4 and C6 will be synthesized. Initially, the C4 side chain will bemaintained unaltered and C6 will be modified. Placement of a plateletactivation factor (PAF)-lipid (16:0) at C6 is expected to improve themembrane adherence characteristics of these compounds. We plan to use ashort (glycine) and a medium spacer (ε-amino caproic acid) as a flexiblepart of the analog providing a connection between the carbocyclic ringand the hydrophobic tail (Scheme 5 and 6). The linker molecule may playin important part in driving the enzymatic hydrolysis of the PAFconjugated fumagillin candidates. The impact of the linker length on thedegradation of phospholipid-prodrug was previously investigated by Dahanet al. ^(28f) A shorter linker (2-carbon) was found to cause a 20-foldless release of the prodrug in comparison to a 5-carbon linker.^(28f)Briefly, ovalicin (or fumaginone) will be treated with ε-amino caproicacid in presence of a mild acidic condition (acetic acid) to afford thecorresponding hydrazone. The hydrazone will be selectively reduced withsodium cyano borohydride followed by DCC/DMAP mediated amidation inpresence of PAF (16:0) resulted analogs-20.

Alternatively, fumagillol will be activated with bis(4-nitrophenyl)carbonate followed by reacting with glycine. In a typical experimentalprocedure, under a N₂ atmosphere, a mixture of fumagillol,bis(4-nitrophenyl) carbonate and DMAP in dry CH₂Cl₂ is stirred for 7 h(scheme 6). The reaction mixture is diluted with CH₂Cl₂ and washed withH₂O. The organic layer is dried (Na₂SO₄) and concentrated. Flashchromatography (EtOAc-hexane) yielded the activated fumagillol. Glycinewill then be coupled to prepare intermediate-6. Briefly, Under a N₂atmosphere, a solution of activated fumagillol, glycine and DMAP in dryCH₂Cl₂ is stirred for 2 h. The completion of the reaction is monitoredby thin layer chromatography. The reaction mixture is worked up bydiluting with CH₂Cl₂ and washing the organic layer with H₂O. Removal ofthe solvent followed by flash chromatography (MeOH-EtOAc) resulted inintermediate-6. Finally a carbodiimide mediated esterification(DCC/DMAP) of intermediate-6 with PAF (16:0) agent will produce analog21.

After placing the PAF agent at C6, the C4 side chain modification offumagillin will be conducted to develop MetAP-2 inhibitors withdesirable pharmacological properties. The spiro epoxide rings of analog18 and 19 will be opened up with thiomethoxide to produce analogs 23 and25. Replacement of the C4 side chain by benzyl oxime and diene sidechains will be pursued to afford analogs 22, 24, 26-27 (Diagram 6).

Characterization of the Synthetic Fumagillin Analogs:

Detailed characterization of the synthetic Fumagillin analogs will beperformed by NMR, FT-IR, mass spectrometry and elemental analyses. The¹H and ¹³C signal assignments and spatial proximity of protons will bebased on COSY, NOE experiments. The ¹H and ¹³C signal assignments willbe made based on COSY, NOESY and selective 1DTOCSY13 measurements. Theproton-proton coupling constants of the aliphatic moiety of the moleculewill be determined by a first-order approximation from the 1H NMRspectrum after Gaussian apodization for resolution enhancement. Theinvestigation of the cyclohexyl ring and the C-4 side chain will be donein a similar ways.

Example 13. Fumagillin Prodrug Efficacy

As shown in FIG. 19, fumagillin dissolved in a lipid membrane rapidlyreleases in vivo, making it practically ineffective in vivo. FIG. 20shows, however, the in vivo effectiveness of a fumagillin prodrugadministered in a nanoparticle of the invention. In particular, thefigure shows the in vivo MR signal enhancement post treatment withtargeted fumagillin nanoparticles (a-b) and control (no drug, c-d);Reduced Matrigel implant volume (%) in rats treated withαvβ3-integrin-targeted nanoparticles with 2.28 mole % fumagillin-PD vs.αvβ3-integrin-targeted nanoparticles with 2.28% fumagillin,αvβ3-integrin-targeted nanoparticles without drug, nontargetednanoparticles with 2.28 mole % fumagillin-PD.

FIG. 21 shows the effect of the fumagillin prodrug in an in vitro cellproliferation assay. The left panel shows the effects of fumagillinprodrug incorporated nanoparticles and control nanoparticles (targetedno drug, non targeted and targeted fumagillin) on human umbilical veinendothelial cells (HUVEC) for cell proliferation by CyQuant NF assay andthe right panel shows cell metabolic activity by Alamar Blue assay.

Example 14. Docetaxel Prodrug

The docetaxel prodrug, synthesized as illustrated in FIG. 18A or B wasadministered to 2F2B cells in an alamar blue assay to measure metabolicactivity. FIG. 22 shows a comparison between an αvβ3 targeted particlewithout docetaxel, an αvβ3 targeted particle with docetaxel, and an αvβ3targeted particle with a docetaxel prodrug. As the assay progressed, theparticle comprising the prodrug demonstrated a sustained suppression ofcell metabolic activity, as compared to the targeted control withoutdocetaxel.

Example 15. Synthesis of Photodynamic Therapy (PDT) Prodrugs

In a typical procedure zinc chelated porphyrin based PDT prodrug will besynthesized in straight forward manner. Amine terminated Zinc-porphyrinPDT prodrug is then subjected to reductive amination with ALDO PC inpresence of NaBH₄ and catalytic amount of trifluoroacetic acid.

Example 16. Polysorbate Micelles

The present application encompasses the design, synthesis,physico-chemical characterization and use of novel nano-particulatesystems for theranostic application and gene delivery system.Multifunctional nanoparticles play a very significant role in cancerdrug delivery. The potential for nanoparticles in cancer drug deliveryis infinite with novel new applications constantly being explored.Cancer has a physiological barrier like vascular endothelial pores,heterogeneous blood supply, heterogeneous architecture etc. For atherapy to be successful, it is very important to overcome thesephysiological barriers. For detection and treatment of cancer usingtargeted molecular imaging and drug delivery, nanoparticulate agents arethe latest achievements in the medical field and form the basis ofnanomedicine research. Various nanodevices has been explored includingNanopores, Nanotubes, Quantum Dots (QDs), Nanoshells, Dendrimers andshell crosslinked nanoparticles, PFC nanoparticles, biodegradablehydrogels etc.

Nanoscale devices are 100 times smaller than human cells but are similarin size to large biomolecules such as enzymes and receptors. In terms ofthe size and shape, nanoparticles smaller than 50 nm can easily entermost cells and those smaller than 20 nm can leave the blood vessels asthey circulate through the body. Nanoparticles are designed as vectorsto carry high payload of contrast agents for efficient detection in vivoand also are suitable to serve as customized, targeted drug deliveryvehicles to carry large doses of chemotherapeutic agents or therapeuticgenes into malignant cells while sparing healthy cells. In thisapproach, nanoparticles greatly reduce or eliminate the oftenunacceptable side effects that accompany many current cancer therapies.The type of nanoparticles is also very important and can be categorizedinto two main classes—inorganic and organic. Liposomes, dendrimers,carbon nanotubes, emulsions, and other polymeric nanoparticles areexamples of widely studied group of organic particles. Most inorganicnanoparticles share the same basic structure of a central core thatdefines the fluorescence, optical, magnetic, and electronic propertiesof the particle, with a protective organic coating on the surface. Thisoutside layer protects the core from degradation in a physiologicallyaggressive environment and can form electrostatic or covalent bonds, orboth, with positively charged agents and biomolecules that have basicfunctional groups such as amines and thiols. In terms of the sizes,inorganic nanoparticles can be produced in a very small sizes rangingfrom 2-50 nm (Gold to iron oxide particles), however it is challengingto achieve such a small size range with organic precursors. Biggernanoparticles in cancer are can make it difficult for them to evadeorgans such as the liver, spleen, and lungs, which are constantlyclearing foreign materials from the body. In addition, they must be ableto take advantage of subtle differences in cells to distinguish betweennormal and cancerous tissues. Indeed, it is only recently thatresearchers have begun to successfully engineer nanoparticles that caneffectively evade the immune system and actively target tumors.

So, despite the recent advances in developing nanoparticles for targetedtherapeutic imaging, there still exists a long standing need in the artfor extravascular particles (<20 nm) water soluble, stable systems.Requisite features include biocompatibility, easily bio-metabolizable,internal sequestration of therapeutic agents, with adjustable releasecharacteristics and tolerance to hostile in vivo environments. Based onthese requirements we developed ultra small “soft” nanocellenanoparticles for theranostic application. The nanoparticles are madespecific to targeted cells or tissues by conjugating to a ligand(integrins αvβ3, α5β□, ICAM-1, VCAM-1, VLA-4 etc.) specific for thetarget cells or tissues. The nanoparticles may further includebiologically active agents, prodrugs (fumagillin, myc-max inhibitor,camptothecin, cis platin, steroids, methotrexate, paclitaxel/docetaxeletc.) radionuclide etc. for their application in imaging and therapy.Particles are incorporated with contrast agents for MR, CT, optical,photoacoustic, PET, SPECT and US.

Preparation of Nanocelle Nanoparticles

We have prepared water soluble nanocelle nanoparticle with a nominalhydrodynamic diameter between 16-20 nm. The core of these particles iscomposed of biologically relevant surfactants (i.e. Tween80, span 80,sorbitan sesquioleate, sorbitan monolaurate) with phospholipids coatingaround it. The particles are thoroughly characterized byphysico-chemical ways.

Typical Procedure for Preparation of avb3-Targeted Myc-Max InhibitorLoaded Nanocelle Particle:

In a typical experimental procedure, the surfactant co-mixture includedhigh purity egg yolk phosphatidylcholine (99 mole %, 395.5 mg),α_(v)β₃-peptidomimetic antagonist conjugated toPEG2000-phosphatidylethanolamine (0.1 mole %, Kereos, Inc, St. Louis,Mo., USA). (1 mole %, 6.0 mg) and 2 mole % of myc-max prodrug. Thesurfactant co-mixture was dissolved in anhydrous chloroform, evaporatedunder reduced pressure to form a thin film, dried in a 50° C. vacuumoven overnight, and dispersed into water (5 mL) by probe sonication.This suspension was combined with the polysorbate mixture (20% v/v, 4ml), distilled, de-ionized water (77.3% w/v, total 15.23 ml) andglycerin (1.7%, w/v, 0.37 ml). The mixture was continuously processedthereafter at 20,000 PSI for 4 minutes with an S110 Microfluidicsemulsifier (Microfluidics) 0° C. The nanocelle particles were dialyzedagainst nanopure (0.2 μm) water using a 20,000 Da MWCO cellulosemembrane for prolonged period of time and then passed through a 0.45 μmAcrodisc Syringe filter. The nanoparticles were stored under argonatmosphere typically at 4° C. in order to prevent any bacterial growth.Hydrated state hydrodynamic diameters (16±4 nm) of the particles aremeasured by Brookhaven dynamic light scattering experiments operatingthe laser at 90°. The de-hydrated state diameter and particle height aremeasured using TEM (negatively stained with 1% uranyl acetate and driedover nickel surface) and AFM (FIG. 30) (tapping mode, drop deposited anddried over glass cover slips) respectively.

Prodrug Testing In Vitro: Cytotoxicity Assays

Human B16 melanoma cells were seeded on a 96 well plate (5000cells/well). After 24 hours, cells were incubated with avb3-integrintargeted nanocelle myc prodrug (˜0.5 uM myc-PD), free myc, targeted nodrug, or nontargeted myc prodrug nanocelles for one hour (6 replicatesper sample per plate). Wells were washed three times with PBS, andplates were returned to the incubator. From two to four days after drugexposure, Cell metabolic activity was measured using an Alamar Blue(Invitrogen). This assay is based on the reduction of nonfluorescent dyeto fluorescent substrate in metabolically active cells. This reductionis typically attributed to different oxidoreductase enzyme systems thatuse NAD(P)H as the primary electron donor. This redox reaction wasmonitored using a fluorescence plate reader (Ex 570 nm, Em 587 nm) wherethe resulting signal is proportional to the number of viable cellspresent. Signal intensity from each sample was normalized to signal fromthe positive control (αvβ3-integrin targeted no drug nanoparticles)(n=3-6 plates per time point) (FIG. 27).

Example 17. Prodrug Comprising PNA

PNAs and conjugates are synthesized on an automated peptide synthesizeron 2 μmol Fmo′c-PAL-PEG-PS according to the standard automated Fmoc PNAsynthesis procedure utilizing commercial monomers (Panagene Inc.,Korea). Following the final step of automated synthesis the resin iswashed with dry DMF (2×3 mL) and dry CH₂Cl₂ (2×3 mL), followed by dryingunder a stream of N₂. The resin will then be shaken in a vial withtrifluoroacetic acid (300 μL) and m-cresol (100 μL) at room temperaturefor 2 h to release and deprotect the PNA. The solution is filtered fromthe resin, and added into ice-cold Et₂O (5 mL) and kept at 4° C. for 1h. The resulting precipitate is collected by centrifugation and purifiedby reverse-phase HPLC. PNA-lysine conjugates are synthesized (2 μmol) onan automated peptide synthesizer using standard Fmoc chemistry.PNA-lysine conjugates in DMSO (0.19 μmol, determinedspectrophotometrically) are added to a solution of PAzPC and allowed tostir for 30 min prior to the addition of1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide methiodide. Theresulting solution was allowed to stir for 16 h and purified by reversephase HPLC technique.

Example 18. Synthesis of Camptothecin Prodrug

a.1) Synthesis of Camptothecin Prodrug 1:

Camptothecin prodrug (1) will be produced by the direct coupling of thecompound with PAzPC (fatty acid modified oxidized lipid16:0-9:0 COOH PC)in presence of DCC/DMAP mediated coupling protocol.

a.2) Synthesis of Camptothecin Prodrug 2:

Camptothecin will be activated with bis(4-nitrophenyl) carbonatefollowed by reacting with monoboc-ethylendimine to produce 6. In atypical experimental procedure, under a N₂ atmosphere, a mixture ofcamptothecin, bis(4-nitrophenyl) carbonate and DMAP in dry CH₂Cl₂ willbe stirred for 7 h. The reaction mixture will be diluted with CH₂Cl₂ andwashed with H₂O. The organic layer will be dried (Na₂SO₄) andconcentrated. Flash chromatography (EtOAc-hexane) will be used to yieldthe activated fumagillol. Monoboc-protected ethylendiamine will then becoupled to prepare intermediate-6. The product will be recovered andimmediately be subjected to DCC/DMAP mediated coupling with PAzPC. Thechemical identity of both analogues will be confirmed by NMR andmass-spectrometric analyses.

Example 19. Methyl Prednisolone Prodrug

Methylprednisolone prodrug is produced by the direct coupling of thecompound with PAzPC (fatty acid modified oxidized lipid16:0-9:0 COOH PC)in presence of DCC/DMAP mediated coupling protocol.

Example 20. Method of Coupling Ligands to the Nanoparticles

Coupling of the ligand to the nanoparticle may be achieved uniquely byfollowing an inclusion compound protocol with β-cyclodextrin (β-CD) onthe particle spontaneously interacting with adamantane on the peptide orsmall molecule ligand to form an inclusion complex. Briefly,cyclodextrin-PEG-DSPE derivative will be synthesized viamono-6-deoxy-6-amino-β-cyclodextrin. One of the seven primary hydroxylgroups of β-cyclodextrin will be tosylated using p-toluenesulfonylchloride. Substitution of the tosyl group by azide and subsequentreduction with triphenylphosphine will yieldmono-6-deoxy-6-amino-β-cyclodextrin. Carboxyl-activated PEG-DSPE will beconjugated to mono-6-deoxy-6-amino-β-cyclodextrin to producecyclodextrin-PEG-DSPE. Adamantane-amine will be directly conjugatedthrough a short spacer in the solid phase peptide synthesis to thecarboxyl end of the peptide to produce adamantane-peptide/ligand. Thesimple room temperature mixing of adamantane-amine and β-cyclodextrinbearing nanoparticle will produce peptide coupled targeted nanoparticle.

The invention claimed is:
 1. A composition for in vivo delivery of ataxane to a target cell, the composition comprising a non-liposomalparticle and at least one taxane prodrug, wherein (a) the particle hasan outer surface that is a membrane comprised of the at least oneprodrug, about 100 mol % to about 60 mol % phospholipid, and a homingligand, and an inner core comprising a surfactant selected frompolysorbate 80, sorbitan monooleate, sorbitan sesquioleate, or sorbitanmonolaurate (b) the particle has a hydrodynamic diameter that is about20 nm or less as measured by dynamic light scattering; and (c) thetaxane prodrug comprises a taxane of less than about 3000 da linked toan acyl moiety of a phosphoglyceride, wherein the taxane may be releasedfrom the phosphoglyceride backbone via enzyme cleavage, and wherein theparticle can leave blood vessels while circulating through the body. 2.The composition of claim 1, wherein the outer surface of the particle iscomprised of not more than 3% of the prodrug.
 3. The composition ofclaim 1, wherein the non-liposomal particle is a micelle.
 4. Thecomposition of claim 1, wherein less than about 10% of the outer surfaceof the particle is cross-linked.
 5. The composition of claim 1, whereinthe outer surface is not pegylated except for the homing ligand.
 6. Thecomposition of claim 1, wherein the homing ligand is selected from thegroup consisting of antibodies, antibody fragments, peptides,asialoglycoproteins, polysaccharides, nucleic acids, small molecules,and peptidomimetics.
 7. The composition of claim 1, wherein the homingligand is selected from the group consisting of integrins αvβ3, α5β1,ICAM-1, VCAM-1 and VLA-4.
 8. The composition of claim 1, wherein thetaxane is linked to the sn-2 acyl moiety of the phosphoglyceride.
 9. Thecomposition of claim 8, wherein the acyl moiety of the prodrug is atleast 4 carbon atoms in length from the glycerol backbone sn-2 esterbond.
 10. The composition of claim 1, wherein the taxane is docetaxel orpaclitaxel.
 11. The composition of claim 1, wherein the prodrugcomprises a compound selected from the group consisting of


12. The composition of claim 1, wherein the phosphoglyceride of theprodrug comprises a phosphoglyceride selected from the group consistingof phosphatidyl choline, phosphatidyl ethanolamine, phosphatidylinositol, and phosphatidyl serine.
 13. The composition of claim 1,wherein the particle has a hydrodynamic diameter that is between about10 nm to about 20 nm as measured by dynamic light scattering.
 14. Thecorn position of claim 1, wherein the outer surface of the particle iscomprised of about 0.1 mol % of the prodrug to about 9% of the prodrug.15. A method for in vivo delivery of a taxane to a target cell, themethod comprising administering a composition to a subject, thecomposition comprising a non-liposomal particle and at least one prodrugin a pharmaceutically acceptable carrier, wherein (a) the particle hasan outer surface that is a membrane comprised of the at least oneprodrug, about 100 mol % to about 60 mol % phospholipid, and a homingligand, and an inner core comprising a surfactant selected frompolysorbate 80, sorbitan monooleate, sorbitan sesquioleate, or sorbitanmonolaurate; (b) the particle has a hydrodynamic diameter that is about20 nm or less as measured by dynamic light scattering; and (c) thetaxane prodrug comprises a taxane of less than about 3000 da linked toan acyl moiety of a phosphoglyceride, wherein the taxane may be releasedfrom the phosphoglyceride backbone via enzyme cleavage, and wherein theparticle can leave blood vessels while circulating through the body. 16.The method of claim 15, wherein the composition is administeredintravenously.
 17. The method of claim 15, wherein the taxane isdocetaxel or paclitaxel.